204 Prof. Pope and Mr Read, The ten Stereoisomeric, ete. t 
The ten Stereoisomeric Tetrahydroquinaldinomethylenecamphors. | 
By Professor Pope and J. Reap, M.A. 
[Read 24 February 1913.] 
THE two enantiomorphously related tetrahydroquinaldines con- 
dense readily with the two similarly related oxymethylenecamphors 
14 
8 
yielding products of the constitution, CyH,,N.CH : OC | . Sineem} 
CO 
each component of the condensation can be obtained in a dextro- | 
and a laevo-rotatory form, four simple optically active condensation 
products can be obtained; the configurations of these may be 
described by the following symbols, in which d- and |- represent — 
the configurations of the tetrahydroquinaldine residue and D- and — 
L- that of the oxymethylenecamphor nucleus. 
(1) d—D. (2) lL. (8) d—L (4) I-D. 
The two members of a pair of enantiomorphously related 
isomerides, (1) and (2), or (3) and (4), combine to form a double — 
or racemic compound, so that the following externally compen- | 
sated substances can also be prepared. ) 
(5) [d—D, 1—L], (6) [d—L, 1—D]. 
Amongst substances such as these, which contain two dissimilar | 
centres of asymmetry, six stereoisomerides of the above types are 
the only ones ordinarily obtainable but in the present instance - 
four more can be prepared. These are the two pairs of partially 
racemic compounds of the configurations stated below. 
(7) {dD} dye) 
(9) [d—D, 1D], (0) [I-—L, d—L}. 
No case has been previously recorded of the formation of 
partially racemic compounds in the manner just described and 
it would be anticipated that no resolution of externally compen- 
sated tetrahydroquinaldine into its optically active components 
would be possible with the aid of d- or l-oxymethylenecamphor. 
It is shown, however, that on treating externally compensated 
tetrahydroquinaldine with less than one-half an equivalent of 
d-oxymethylenecamphor a resolution can be effected because the — 
l-base condenses more rapidly than the d-isomeride with d-oxy- — 
methylenecamphor; under these conditions the condensation 
yields about 80 per cent. of the partially racemic compound (9) 
and 20 per cent. of the simple optically active substance (4) from 
which |-tetrahydroquinaldine may be separated. 
